In a structure forming a larger light emitting device by arranging a plurality of planar light-emitting panels using organic electroluminescence (EL) and the like, a non-light emission region existing in a periphery of a light source of plane light emission is dark. Therefore, a luminance difference is generated between a light-emitting portion and the non-light emission region. Therefore, a problem to be solved is how to obtain a uniform light-emitting surface without having any unevenness by making a luminance on a non-light-emitting portion at a joint between a planar light-emitting panel and a planar light-emitting panel approximate to a luminance on a light-emitting portion.
As a related art, a configuration of reducing a luminance difference by providing a diffusion member on a light source at a predetermined distance space is disclosed in JP 2005-353564 A (Patent Literature 1). Additionally, a configuration of reducing a luminance difference by disposing light guide member 20 on a light source and performing light extraction only from a non-light emission region by embedding diffusion particles only on the non-light emission region inside the light guide member 20 is disclosed in JP 2005-158369 A (Patent Literature 2).